An earthquake is caused by the sudden displacement of rock in the Earth's crust due to crustal strain, volcanoes, landslides, or collapsing caverns. Earthquakes can cause ground shaking, landslides, fires, soil liquefaction, tsunamis, floods, and damage human infrastructure. Soil liquefaction occurs when saturated granular soils like silty sands or sandy gravels lose strength during an earthquake or sudden stress change and behave like liquid, which can damage buildings and cause them to sink or tilt.

1. Prepared by : Nariman Dehghani

2. Earthquake
An earthquake is the motion or
trembling of the ground
produced by sudden
displacement of rock in the
Earth's crust. Earthquakes
result from crustal strain,
volcanoes, landslides, and
collapse of caverns.

3. The effects of earthquakes include, but are
not limited to, the following:
Shaking and ground rupture
Landslides
Fires
Soil liquefaction
Tsunami
Floods
Human impacts

4. Earthquake Effects - Ground Shaking
Northridge, CA 1994

5. Earthquake
Effects -
Ground Shaking
Northridge, CA 1994

6. Earthquake Effects - Ground Shaking
Loma Prieta, CA 1989

7. Earthquake Effects - Ground Shaking
Kobe, Japan 1995

8. Earthquake Effects - Ground Shaking
Kobe, Japan 1995

9. Earthquake Effects - Surface Faulting
Landers, CA 1992

10. Earthquake Effects - Liquefaction
Niigata, Japan 1964

11. Earthquake Effects - Landslides
Turn again Heights, Alaska,1964 (upper left inset);
Santa Cruz Mtns, California , 1989

12. Earthquake Effects - Fires
Loma Prieta, CA 1989

13. Earthquake Effects - Tsunamis
1957 Aleutian Tsunami

14. Soil liquefaction describes a
phenomenon whereby a saturated soil
substantially loses strength and
stiffness in response to an applied
stress, usually earthquake shaking or
other sudden change in stress
condition, causing it to behave like a
liquid.
Liquefaction

15. Liquefaction occurrence:
Liquefaction is more likely to occur
in loose to moderately saturated
granular soils with poor drainage,
such as silty sands or sands and
gravels capped or containing seams
of impermeable sediments.

18. Earthquake liquefaction:
The pressures generated during large
earthquakes with many cycles of
shaking can cause the liquefied sand
and excess water to force its way to the
ground surface from several meters
below the ground.

20. Effects:
The effects of soil liquefaction on the
built environment can be extremely
damaging. Buildings whose foundations
bear directly on sand which liquefies will
experience a sudden loss of support,
which will result in drastic and irregular

21. settlement of the building causing
structural damage, including cracking of
foundations and damage to the building
structure itself, or may leave the structure
unserviceable afterwards, even without
structural damage.

24. Niigata Japan 1964

25. Loma Prieta 1989

33. Kobe Japan 1995

35. Niigata 1964